GRIMM-TYPE GLOW-DISCHARGE ION-SOURCE FOR OPERATION WITH A HIGH-RESOLUTION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY INSTRUMENT

A GD ion source of the Grimm-type design has been developed for operat ion with a new commercial double focusing ICP-MS instrument capable of higher mass resolution. Instead of introducing only the sample, a com plete source arrangement is introduced into the housing of the MS syst em through a slide valve by a solid insertion probe. Sample changing a nd source cleaning is fast and the latter reduces the risk of cross co ntamination to a minimum. The reproducibility of the positioning of th e sample and the source is verified by measuring 'internal' (reproduci bility of the intensity measurements) and 'external' (the analysis as a whole when sample changing is included) reproducibilities in analyti cal determinations. Over the whole mass range, the sensitivity corresp onds to that measured with an almost identical GD ion source and a low resolution quadrupole instrument. This demonstrates that element sens itivities are predominantly determined by the processes taking place i n and the geometry of the source and not by the ion optics and mass an alyser components.